Downhole mechanisms

ABSTRACT

Apparatus and procedures whereby, downhole, a fluid is heatable as a consequence of heat exchange from a matrix downhole being heated responsive to downhole varied magnetic fields on the matrix. This can involve a fluid or mechanical input to rotate a magnetic array relative to the matrix, or vice versa.

The present invention relates to downhole mechanisms. The downhole mechanisms of the present invention are adapted to provide heat to a fluid in a downhole situation eg, possibly as a downhole steam generator for hydrocarbon recovery.

There are many instances where there is a desire to introduce heat into a bore whether for recovery of hydrocarbons or otherwise. This may or may not be whilst the drillstring is still within the bore.

Frequently when a heated fluid or pyrolysis is required downhole there has been resort to generating a heated fluid from an uphole and directing that down through insulated ducting downhole. In other situations heat has been generated downhole reliant upon electrical resistance heating or by ignition of a combustible substance.

The present invention recognises an advantage for one or more downhole heat exchange mechanisms that are not reliant upon electrical input but rather can rely, if wanted, solely upon a drive from fluid and is able to direct all or part of that driving fluid, once heated, into the subterranean formation. In some instances it may be desirable to use more fluid than is actually required to egress to ensure that desired temperatures are reached. In such circumstances some of the fluid will be directed back uphole with only a portion of the fluid egressing. In other situations there may be sufficient heating for the purpose, whatever the purpose may be, in passing all of a fluid flow out into a surrounding subterranean formation.

It is therefore an object of a present invention to provide for downhole heating of a fluid stream.

It is a further or alternative object of the present invention to provide apparatus, assemblies, methods, procedures and systems (or the use of any of them) for the purpose of introducing heat into a subterranean formation or at least maintaining or introducing heat into a fluid stream to be brought into contact with such a subterranean formation.

In an aspect the invention is the use (preferably downhole) of a matrix (preferably solid ie, not involving a working fluid) to heat directly or indirectly a fluid by heat exchange, the matrix being heated as a consequence of movement of at least one magnet relative thereto, or vice versa, or both.

Preferably the relative movement is as a consequence of rotation of either or both the matrix and/or at least one magnet.

Optionally the relative movement is a relative reciprocation.

Other movement types are capable of generating heat eg, oscillating movements, hybrid movements with both a rotational and other component of movements, etc.

Preferably a spindle carries multiple magnets and that is caused to rotate relative to a matrix that fully or partially surrounds the spindle carried magnets.

Without wishing to be bound by theory, it is believed eddy currently induced by the magnet(s) in the matrix cause the heating of the matrix. For such eddy currents to occur the matrix is of a conductive material with available elections (material of low electrical resistivity).

In another aspect the invention is a method of flushing with a heated fluid downhole, said method comprising or including the steps of passing a fluid downhole to cause relative movement between at least one magnet and a matrix heatable by such relatively of movement and, by heat exchange involving at least said matrix, heating at least some of that fluid prior to its egress downhole.

Preferably the fluid is water.

Preferably steam egresses.

Preferably a positive displacement motor cause the relativity of movement.

In another aspect the invention is the use of a hot fluid for hydrocarbon recovery where the fluid has been heated using heat exchange directly or indirectly from a heated matrix heated as a consequence of relative movement of at least one magnetic or heated matrices each heated as a consequence of relative movement of at least one magnet.

Preferably a positive displacement motor cause the relativity of movement.

In another aspect the invention consists in apparatus to provide a heated fluid into a surrounding underground structure, said apparatus comprising or including ducting for the intake and passing of a fluid down a borehole to at least one outlet from which the fluid, once heated, can egress, and at least one heat exchange assembly through which the fluid is ducted to be heated between the intake(s) and outlet(s) of the ducting, the or each heat exchange assembly having at least once matrix to be heated as a consequence of relative movement of at least one magnet, such relative movement being caused by the ducted fluid.

It is a further aspect of the present invention to provide a method or apparatus of any of the aforementioned kinds, or the use of any of the aforementioned kinds, wherein, whether alone or in series, there is heat exchange as a result of the relative movement between at least one matrix and a matrix in association therewith heatable by such relativity of movement but where a fluid is used to provide the relativity of movement and either all, or some only, of that fluid is released to the subterranean formation.

In some circumstances in order to maintain higher temperatures than would be the case were all of the fluid to be subjected to the heat exchange, some of the fluid may be returned uphole.

In some forms of the present invention one or more fluids can be utilised.

In other forms mixtures of fluids can be utilised eg, steam and water.

In still other aspects compressed air and water can be used to last whether in a mixture or separately.

Preferably the arrangement is substantially herein after described. It should be realised however that the drawings show but one exemplification of a single stage heat exchange able to be used in a ducted single stream or ducted split plural streams to raise temperatures and optionally allow a phase change.

In another aspect the invention is an apparatus to provide a heated fluid into a surrounding underground structure, said apparatus comprising or including ducting for the intake and passing of a fluid down a borehole to at least one outlet from which the fluid, once heated, can egress, and at least one heat exchange assembly through which the fluid is ducted to be heated between the intake(s) and outlet(s) of the ducting, the or each heat exchange assembly having at least once matrix to be heated as a consequence of relative movement of at least one magnet, such relative movement being caused by a drill rod.

In still another aspect the invention is an apparatus for downhole use to generate a hot liquid and/or gaseous fluid from a fluid being passed downwardly, said apparatus comprising or including

a tubular casing,

a sleeve or surround within the tubular casing, one or other, or both, of the casing and sleeve or surround being fluted or finned to divide the fluid being passed into streams for heat exchange from the fluted sleeve or surround and/or the tubular casing,

a spindle to rotate within the fluted sleeve or surround, the spindle carrying magnets able to generate heat in the fluted sleeve or surround and/or the tubular casing to, at least in part, be transferred to the fluid, and

a drive to rotate the spindle.

In yet a further aspect the present invention consists in hydrocarbon recovery utilising any of the aspects of the present invention.

In still a further aspect of the present invention consists in apparatus substantially as hereinafter described with reference to any one or more of the accompanying drawings.

As used herein the term “and/or” means “and” or “or”, or both.

The terms “directly” or “indirectly” and “direct” or “indirect” in respect of the vibration arising from hammering refers unidirectional or bidirectional transmission via one or other of the components involved with the hammering.

As used herein “(s)” following a noun means the plural and/or singular forms of the noun.

As used herein “hydrocarbon” includes oil.

Two preferred forms of the present invention will now be described with reference to a downhole steam generation arrangement.

FIG. 1 showing, as a part section isometric view, a tube having a fluid motor (eg, mud motor) to the left able to rotate a spindle (magnetic magnet rotor) driven by the fluid motor,

FIG. 2 is the front view from the left end end of the apparatus of FIG. 1,

FIG. 3 is a section AA of the apparatus of FIG. 2,

FIG. 4 shows an isometric view in part section of a second embodiment where a drill rod or a shaft supplies rotation,

FIG. 5 shows a front view of the embodiment of FIG. 4,

FIG. 6 is a sectional view at B-B of the embodiment of FIGS. 4 and 5 and the detail “A” of FIG. 7, and

FIG. 7 shows drill site set up using an embodiment of the invention.

In a preferred form of the present invention the water path is substantially as shown as a flow in FIG. 3.

The spindle one includes a plurality of permanent magnets arrayed therearound so as to provide an outstanding magnetic field. These magnets are to spin relative to the stationary sleeve 3 (eg, of a conductor such as aluminium). The sleeve is fluted so as to provide good heat exchange contact with the water paths shown so as to provide, for all of the water passing through, the prospect of being raised at one stage (or by a series of such stages) to a required temperature, whether still as water or, as indicated, steam.

The positive displacement motor 4 is driven by the water making contact therewith prior to receiving a further increment of heat or being fully heated by heat exchange between the outer (preferably insulated) casing 5 and the fluted conductive (both heat conductive and electrically conductive) sleeve 3.

In the arrangement shown the aluminium sleeve 3 remains stationary with respect to the outside sleeve as does the casing 6 which is outside of the positive displacement or fluid motor (eg, a mud motor).

In the embodiment of FIGS. 4 and 5 in a preferred form of another embodiment as shown in FIGS. 4 to 6 there is a magnetic rotor 7 having magnets arrayed about a preferably expanded continuation of the drill rod or equivalent rotational input 10. This array of magnets 8 of the magnetic rotor 7 is enclosed in a stationary aluminium enclosure having fins that define passageways 9A between the aluminium and the casing 11.

In this mode of operation ie, with rotation only of the magnetic arrays water can pass in and through the passageways 9A and thereby be heated by the eddy currents passed by the spinning magnets into the aluminium surround. The aluminium sleeve 9 preferably includes multiple outwardly extending fins or fluting so as to provide multiple passageways 9A.

In use the arrangement as shown in FIGS. 4 to 6 (or indeed the embodiment shown earlier) can be used, for example, as shown in FIG. 7.

In the embodiment of FIG. 4 a casing of a drill string or drill rod passes down to that downhole zone “A” shown, as one example, in more detail in FIG. 6. The ground level is 13 and the vertical drill rig with which the apparatus is used is shown as 12.

This embodiment may allow more power to be passed downhole than with a mud motor.

It can be readily visualised that whilst a rotary relativity of movement has been used to induce heating, the heating of the aluminium sleeve could instead be caused by reciprocation or some mixture of reciprocation and rotation. This can apply to both embodiments discussed.

Other suitable materials for the sleeve besides aluminium can be utilised. For example eg, conductive metals including iron, steel, copper, aluminium, precious metals, etc or alloys including any such metals. There can even be sintered or other aggregated masses used.

The suitable materials for the casings 6 or 11 can be any metal that has a low electrical resistivity (able to transmit heat easily). For example any of the above mentioned metals or alloys.

A suitable permanent magnetic material useful for the present invention is preferably one that can withstand temperatures of for example up to 370° C. Examples include Rare Earth type magnets of high magnetic density, eg, Neodymium magnets, such as those of NdFeB, can be stable to 180° C. and Samarium Cobalt magnetic (FmCo) which can be used up to 400° C.).

Other forms of magnet can be utilised including those magnets that may be developed in the future.

The material(s) to support the magnetic material can be any suitable material with a structural integrity to support the forces eg, metals and alloys as above, composites, resin systems, etc.

Temperature increase will depend on temperature available from the conductor to transfer to the fluid, the efficiency of such transfer, heat losses, fluid flow volume and speed, specific heat of the fluid and whether any phase change occurs.

The temperature of conductor will depend on speed relativity, choice of conductor and choice and geometry of the magnetic array, magnetic flux density, etc. 

1. A use of a solid matrix to heat directly or indirectly a fluid by heat exchange, the matrix being heated as a consequence of movement of at least one magnet relative thereto, or vice versa, or both.
 2. The use of claim 1 downhole to generate steam and/or hot water.
 3. The use of claim 1 wherein the relative movement is as a consequence of rotation of either or both the matrix and/or at least one magnet.
 4. The use of claim 3 wherein a spindle carries multiple magnets and that is caused to rotate relative to a said matrix that fully or partially surrounds the spindle carried magnets.
 5. A method of flushing with a heated fluid downhole, said method comprising or including the steps of passing a fluid downhole to cause relative movement between at least one magnet and a matrix heatable by such relatively of movement and, by heat exchange involving at least said matrix, heating at least some of that fluid prior to its egress downhole.
 6. The method of claim 5 wherein the fluid is water.
 7. The method of claim 5 wherein steam egresses.
 8. The method of claim 5 wherein a positive displacement motor cause the relativity of movement.
 9. The method of claim 5 wherein a drill rod causes the relativity of movement.
 10. A use of a hot fluid for hydrocarbon recovery where the fluid has been heated using heat exchange directly or indirectly from a heated matrix heated as a consequence of relative movement of at least one magnetic or heated matrices each heated as a consequence of relative movement of at least one magnet.
 11. An apparatus to provide a heated fluid into a surrounding underground structure, said apparatus comprising or including ducting for the intake and passing of a fluid down a borehole to at least one outlet from which the fluid, once heated, can egress, and at least one heat exchange assembly through which the fluid is ducted to be heated between the intake(s) and outlet(s) of the ducting, the or each heat exchange assembly having at least once matrix to be heated as a consequence of relative movement of at least one magnet, such relative movement being caused by the ducted fluid.
 12. An apparatus to provide a heated fluid into a surrounding underground structure, said apparatus comprising or including ducting for the intake and passing of a fluid down a borehole to at least one outlet from which the fluid, once heated, can egress, and at least one heat exchange assembly through which the fluid is ducted to be heated between the intake(s) and outlet(s) of the ducting, the or each heat exchange assembly having at least once matrix to be heated as a consequence of relative movement of at least one magnet, such relative movement being caused by a drill rod.
 13. An apparatus for downhole use to generate a hot liquid and/or gaseous fluid from a fluid being passed downwardly, said apparatus comprising or including a tubular casing, a sleeve or surround within the tubular casing, one or other, or both, of the casing and sleeve or surround being fluted or finned to divide the fluid being passed into streams for heat exchange from the fluted sleeve or surround and/or the tubular casing, a spindle to rotate within the fluted sleeve or surround, the spindle carrying magnets able to generate heat in the fluted sleeve or surround and/or the tubular casing to, at least in part, be transferred to the fluid, and a drive to rotate the spindle.
 14. The hydrocarbon recovery utilising a method of claim
 5. 15. (canceled) 